Release Android Preview 21 and bilingual changelog

Add permission-based reading of Android contacts, SMS and call history. Include shared Gaia fixes and document device validation limits. Pixel image qualification remains pending.

tests/settings-startup.test.mjs

@@ -0,0 +1,19 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import vm from 'node:vm';
+import {readFileSync} from 'node:fs';
+const source=readFileSync(new URL('../gaia/apps/settings/js/startup.js',import.meta.url),'utf8');
+const bootstrap=source.slice(source.lastIndexOf('(function() {'));
+test('Settings waits for deferred components before loading AMD modules',()=>{
+  let starts=0;
+  const document=Object.assign(new EventTarget(),{readyState:'interactive'});
+  vm.runInNewContext(bootstrap,{document,AppStarter:()=>({start:()=>starts++})});
+  assert.equal(starts,0);
+  document.dispatchEvent(new Event('DOMContentLoaded'));assert.equal(starts,1);
+  document.dispatchEvent(new Event('DOMContentLoaded'));assert.equal(starts,1);
+});
+test('Settings starts immediately when loaded after the document',()=>{
+  let starts=0;
+  vm.runInNewContext(bootstrap,{document:{readyState:'complete'},AppStarter:()=>({start:()=>starts++})});
+  assert.equal(starts,1);
+});